The durability of spray steel fiber-reinforced recycled coarse aggregate concrete

To boost the application scope of coarse recycled aggregates (RA) with particle size in the range of 5-10 mm, a spray steel fiber reinforced coarse aggregate concrete (SSFRCAC) is developed, and the impact of cube compressive strength, RA replacement ratio, and steel fiber (SF) volume fraction on the durability of SSFRCAC is comprehensively examined through carbonization, sulfate attack, penetration, and freeze-thaw cycle tests. The anti-carbonation test results reveal that as the RA replacement ratio increases, the carbonation resistance of SSFRCAC decreases. The best anti-carbonation performance is achieved when the SF volume fraction is 1%. Additionally, a formula for calculating the carbonation depth is established. Based on the experimental data, the dynamic elastic modulus is recommended as the measurement standard for the freeze-thaw resistance cycle test. The sulfate resistance test results indicate that as the RA replacement ratio increases, the Sulfate Resistance coefficient also increases. SF block the thermal cracks of specimens and corrosion products as well as the formation of expansion cracks, so the corrosion resistance coefficient gradually tends to a certain stable level. According to the anti-permeability test results, the increase in the RA replacement ratio can suppress the antipermeability performance. When the SF volume fraction is 1%, the concrete has the highest density and the best anti-permeability performance. Overall, the durability of SSFRCAC is found to be much better than that of general recycled SF Recycle aggregates concrete, which makes it more suitable for practical engineering applications.